1. Field of the Invention
The invention relates to a cooling apparatus, in particular for the air-conditioning of a vehicle passenger compartment. The cooling apparatus includes a housing and a plurality of chambers arranged therein, sealed tightly and filled with a storage medium. The chambers are combined to form a block and at least one passage is provided between each pair of adjacent chambers. Each of the passages is connected to distribution and collection chambers formed in the housing with at least one feed port and a return port.
2. Description of the Related Art
U.S. Pat. Ser. No. 5,644,929 relates to a cooling apparatus for a vehicle cabin. The cooling apparatus includes a heat regenerating evaporator encased in a case and provided with a tube for a cooling medium and a heat regenerating pack arranged to be in close contact with the outer surface of the tube of the heat regenerating evaporator. The heat regenerating evaporator conducts a refrigeration cycle while a vehicle is running and cools the heat regenerating pack to freeze the heat regenerating material within the pack. When the vehicle is parked, a blower is operated to produce a current of air that is cooled by the heat regenerating pack due to heat exchange between the current of air and the frozen heat regenerating material in the heat regenerating pack. The cold air is blown out into an selected cooling area, such as a sleeping area of the vehicle, from a vent so that the selected cooling area is air-conditioned.
European Patent No. 839,679-A2 relates to a device for cooling a vehicle passenger compartment. The device includes a first coolant circuit which has a compressor, a condenser and at least one evaporator. In addition, there is a second coolant circuit which includes at least a second evaporator connected to an ice reservoir to form a structural unit. There are also valve means, by which the evaporator arranged in the ice reservoir can be operated in parallel with the evaporator of the air-conditioning unit. According to the patent, there is provision for the structural unit including the ice reservoir and second evaporator to be arranged as a sheet-like element in a wall of the vehicle passenger compartment and to provide air-guide ducts which allow direct heat exchange with the air fed to the passenger compartment of the vehicle.
The prior arrangements require considerable construction outlay, in particular with regard to the additional components of the coolant circuit, and this has an adverse effect on production costs. Moreover, it is difficult to insulate the prior cooling apparatus, owing to the air-guide ducts.
An object of the invention is to overcome the disadvantages of the known art. The present invention is based on the object of providing a cooling apparatus of the generic type which allows the construction outlay to be reduced and makes the accumulator more versatile.
One object of the present invention is to provide a cooling apparatus which includes a housing having a plurality of chambers arranged therein, wherein the chambers are sealed tightly and are filled with a storage medium; passages which carry a heat-transfer medium and extend between the chambers, the chambers of a group being combined to form a block; and at least one passage provided between each pair of adjacent chambers, wherein each of the passages is connected to distribution and collection chambers formed in the housing and wherein the housing includes at least one feed port and at least one return port.
In one aspect of the invention, the cooling apparatus includes components of simple structure that can be well insulated against thermal radiation. The cooling apparatus is charged and discharged by means of a single heat-transfer medium, so that only connections and feed lines for a single heat-transfer medium are required. To facilitate handling during installation in the housing and while securing its position therein, it is desired that the chambers are held at a predetermined distance apart by support means. Preferably, two or more blocks may be arranged side-by-side next to one another or above one another, according to the desired storage capacity in the housing. This arrangement of blocks leads to a modular structure of standardized components, by which it is possible to take suitable account of the conditions required. The housing preferably has a substantially cuboid-shaped and is provided with an attachment means.
In another aspect of the invention, the apparatus includes four side walls and a base of the housing that form a box-like component which, on its side opposite from the base, forms an insertion opening through which the block or blocks can be inserted. The insertion opening is closed in a sealed manner by a cover. According to one embodiment of the housing, the latter is made from aluminum sheet, while the wall parts and the base are preferably connected to one another by a material-to-material bond and are therefore sealed together. The housing may be surrounded by an insulating jacket or, in the case of a sandwich structure, may be filled with insulating material, to minimize thermal losses. As an alternative, the housing may be formed of a plastic material which, if it is of suitable wall thickness, has a thermally insulating action. A representative wall thickness is preferably between about 20 mm and about 30 mm. The housing can be easily produced in a single piece so that only the cover needs to be produced as an individual component and subsequently fitted, thereby improving manufacturing of the device.
Another object of the invention is to provide a housing which includes an end side which faces the distribution or collection chamber forming the insertion opening, while all the other sides are closed housings. In this embodiment, the outer wall of the distribution or collection chamber functions as the cover and can be fitted and sealed on the device. In the case of plastic housings, the cover and housing can be connected in a sealed manner by a suitable welding process. Possible alternatives to welding process include adhesive bonding or a mechanical connection, for example, bracing, in which case a seal may have to be added.
According to another aspect of the invention, the storage medium in the chambers is preferably tap water, in which case the chambers are to maintain, in addition to the storage medium, a residual gas volume of preferably from about 10% to about 20%. This residual volume is advantageous in view of the change in volume of the storage medium during phase transition. As an alternative, it is also possible to provide an absorbent material, such as for example a nonwoven or cellulosic material, in which case the absorbent material is completely impregnated and then placed into the chambers.
It is also an object of the invention to be able to handle the storage medium easily during manufacturing. To achieve this object, the storage medium may include a mixture of water with a gelling agent. The storage medium, which is in a gel form at room temperature, may then be introduced into the individual chambers of the containers. The thickening agent has an additional advantage in reducing the amount of steam which may be formed as a result of the introduction of heat when the cover is sealed to the frame, thereby increasing the strength of the weld or seal seam. The gelling agent used is preferably a hydrogel material and more preferably includes a crosslinked, partially neutralized polyacrylic acid. The hydrogel is preferably present in the storage medium in an amount of from about 0.5% by weight to about 30% by weight of the storage medium, most preferably between about 1% by weight and about 2% by weight of the storage medium. These ratios have proven to represent a particularly appropriate compromise between the storage capacity of the storage medium, on the one hand, and its processibility, on the other hand. However, it should be understood that the invention is not so limited.
In yet another aspect of the invention, the chambers may be designed as cold storage elements which have a dimensionally stable frame, the frame being spanned on both sides by a cover to form the cold storage apparatus. Cold storage elements which are designed in this way may advantageously be stacked without further, separate intermediate elements. Thus, it is possible to dispense with the spacers to form flow passages. This alone makes it possible to produce the cooling apparatus at considerably lower cost, since to construct the cold storage apparatus it is only necessary for the chambers, which have been filled with a storage medium and closed to then be stacked above one another in the housing of the cooling apparatus. Therefore, in this alternative arrangement, the cooling apparatus elements are able to perform the three main functions, namely, holding the storage medium, forming the flow passages and fixing the position of the cooling apparatus elements inside the housing. The modular structure makes it possible to produce a wide range of structural forms, since, for example, it is possible to arrange a plurality of stacks of cooling apparatus elements next to one another.
It is another object of the invention to provide an apparatus by stacking the chambers directly in the housing of the cooling apparatus, without intermediate elements to achieve a greater packing density for a given volume. Thus, the space required by the cooling apparatus can be reduced while maintaining a constant output capacity. Furthermore, it is possible to increase the capacity of the cooling apparatus compared to cooling apparatus of the prior art while still achieving a reduction in the space required. The chambers, with their dimensionally stable frames, are easy to handle in terms of manufacturing technology, so that it is possible to automate assembly of the cooling apparatus and thus to manufacture the accumulator at lower cost.
In another aspect of the invention, the stability and ease of handling of the chambers are further improved by support webs that are arranged inside the frame. The support webs are advantageously of the same height as the frame, such that individual spaces are formed inside the chamber when the cover is connected to the frame and the support webs. The volume of storage medium which is held in the cold storage element may then divided into smaller volumes, so that it is possible to avoid or reduce sloshing noises when the cooling apparatus moves, for example, when driving. Also, smaller volumes are easier to handle in the event of automated filling of the chambers with the storage medium. A further advantage of the support webs is the improved strength of the cover, which is connected to the support webs. Furthermore, the formation of chambers ensures that the cooling apparatus will function reliably even when it deviates from a preferably horizontal position, and in particular during freezing.
The cover used may be an inexpensive flexible laminated film or foil, preferably an aluminum composite foil. A foil of this nature on the one hand fulfills the requirement for a highly flexible cover, in order to be able to accommodate the expansion caused by temperature-related changes in volume of the storage medium. On the other hand, the low diffusion rates which are required for long-term operation can be achieved.
In principle, the individual chambers may be of any desired shape. For strength reasons, it is preferable for the support webs to be arranged in such a way that the chambers have a hexagonal contour.
In another aspect of the invention, flow passages for the heat-transfer medium are formed between the stacked cooling apparatus elements by suitable shaping of the frame. For this purpose, spacers may be provided on the frame, which spacers are preferably designed, in the most simple way, as web-like elevations which run on the longitudinal sides in the direction of flow. If the spacers are arranged in such a manner that cooling apparatus elements which are stacked above one another are held in a fixed position in the transverse direction with respect to the elevations, the cooling apparatus elements are thus fixed in place relative to one another.
In another aspect of the invention, support elements may be arranged on the outside of the frame. Thus, it is possible for the cooling apparatus element to be held fixed in position relative to the housing. The cooling apparatus then essentially comprises only the housing and the cooling apparatus elements which are inserted in the housing by simple stacking.
According to yet another aspect of the invention, the chambers may include a flexible enclosure made from plastic material, where the ends of the enclosures are welded, bonded or sealed together in another suitable way. Depending on the nature of the plastic enclosure, it may be advantageous to fix the flat sides of the enclosure together at predetermined intervals, for example, in such a way that a plurality of joined cushions are formed from one enclosure. Therefore, in the case of enclosures which are made from material which is not dimensionally stable, the length of the individual chambers is limited. This can reduce the geodetic loads on a slope, for example, when driving uphill or downhill. Flattened tubes which serve as passages for the heat-transfer medium are expediently provided as support means between the enclosures.
If a greater block depth, that is to say the longitudinal extent in the direction of flow of the heat-transfer medium, is provided, at least two flexible enclosures may be arranged behind one another in the longitudinal direction of the passages. If appropriate, measures can be taken to fix the position of the enclosures in the longitudinal direction.
It is another object of the invention to provide a particularly suitable structure of a block which includes chambers and passages having two parallel side strips and, between them, a bearing section for the enclosures are provided, in which case the profile elements are stacked on top of one another. The bearing section may be corrugated in cross section, in which case the enclosures contact the corrugation peaks, and intermediate spacers which serve as passages for the heat-transfer medium may be formed between the corrugation valleys and the enclosures. Another configuration of the bearing section includes an elongate web between the side strips and provides support elements formed integrally on the top side and the underside, in which case the enclosures contact the support elements, and the passages for the heat-transfer medium are formed between these support elements on each side.
The cooling apparatus can be adapted to any particular installation conditions, i.e. the space available, in a simple manner. Account is also taken of what length of passages for the heat-transfer medium is appropriate to achieve an optimum heat exchange. The length of the chambers may be between about 200 mm and about 300 mm, preferably from about 250 mm to about 260 mm. The width of the chambers may be from about 100 mm to about 150 mm, preferably about 125 mm, and their height of the chambers may be from about 10 mm to about 20 mm, preferably about 14 mm.
The heat-transfer medium used maybe , for example, a glycol mixture, the freezing point of which is suitably low. However, other cooling agents may also be suitable, in particular salt solutions which, for reasons of corrosion resistance, may be in the form of NaCl, CaCl2 or MgCl2.
The above and other advantages and features of the invention will be more clearly understood from the following detailed description of preferred embodiments which is provided in connection with the accompanying drawings.